Modern integrated circuits (ICs) are made up of literally millions of active devices such as transistors and capacitors. These devices are initially formed individually on a substrate, but are later interconnected together to form functional circuits. Typical interconnection structures include lateral interconnections, such as metal lines (wirings), and vertical interconnections, such as via plugs. On top of the interconnection structures, bond pads are formed and exposed on the surface of the respective chip. Electrical connections are made through bond pads to connect the chip to a package substrate or another die.